Furnace.



F. SIEMENS. FURNAGE.

APPLIOATION I'ILED JUNE 13, 1912.

'1,098,985. Patented June 2, 1914.

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F. SIEMENS.

FURNACE.

v APPLIOATION PILED JUNE 13, 1912. 1,098,985 v Patented June 2, '1914.-

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F. SIEMENS,

FURNAGE.

APPLIGATION FILED JUNE13,1912. 1,0-98,985, Patented June 2, 1914.

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F. SIEMENS.

PURNAGE. APPLIL'ATION PILED JUNE 13, 1912.

1,098,985. V Patented June 2, 1914.

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W//// A L I /V/A//// w UNITED STATES P TENT OFFICE.

FRIEDRICH SIEMENS, OI' BERLIN, GERMANY.

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Specification of Letters Patent.

Patented June 2, 1914.

Application filed June 13, 1912. serial No. ?03,554.

exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in open hearth furnaces of the regenerative or recuperative type, and more particularlyin open hearth furnaces of that class, in which the hearth consists of two sections adapted to be heated to different temperatures, and in which a part of the flarne heating the section of higher temperature is directed through the section of lower temperature, while the remaining part of the said flane is used for heating the regenerator or recuperator. A furnace of this class has been described in my Austrian Patent No. 51,838 dated March 10, 1910. As explained in the specificaton of the said patent, the flame which passesexclusively through the chamber of the furnace of higher temperature has a form which is similar to a horse shoe located in a horizontal plane.

One of the objects of the improvements is to provide a furnace of this class in which the flame is not` necessarily formed in a horizontal plane, but can assume any desired position relatively to the hearth or. furnace. Thereby my improved system can be ut to use under various conditions under which it can not be used when the flame is formed in a horizontal plane When heating in the furnace materials which give off much dust, the flame which is taken from the chamber of higher temperature and directed through the regenerators carries along much dust whereby the re enerators are rapidly choked. To avoid ths I prefer to provide a subsidiary cham- 'ber in front of the discharge ends of the burners and intermediate the letter and the heating chamber of the furnace, and todirectly connect the said subsidiary chamber with the regenerators, so that the regenerators are heated by gases which have not been in contact with the material to be heated, and which are therefore free of dust. The gases are conducted in such a way, that they are divided within the chamber which is provided between the discharge of the burners and the hearth and does not receive the material to be heated, one part of the gases passing directly through the regenerator and another one through the whole furnace.

In order that my invention may be more clearly understood several examples embodying the same have been shown in the accompanying drawings, in which the same letters of reference have been used in all the views to indicate corresponding parte.

crosssection of a furnace in which the fiues for admitting and withdrawing the heating gas are disposed vertically and laterally and on opposite sides of the section of the hearth of high temperature, so that the horse shoe shaped'flame is formed in a vertical plane perpendicular to the longitudinal aXs of the :hearth, Fig. 2, is a horizontal section of the furnace shown in Fig. 1, Fig. 3, is a longitudinal section of a furnace in which the nlet and outlet fiues are disposed at the rear and on opposite sides of a subsidiary chamber located at the rear of the hearth, and in which the upper wall of the said chamber is inclined forward and upward, so that the flame is formed in an inclined plane, Fig. 4, isa horizontal section of Fig. 3, Fig. 5, is a longitudinal section of a furnace in which rear of the hearth and above each other, so that the flame is formed in a vertical planelocated in' the direction of the longitudinal axis of the furnace, Fig. 6, is a horizontal section of Fig. 5, Fig. 7, is a longitudinal section of the rear part of a furnace in which the inlet and outlet fiues are disposed at the rear of the hearth and above each other and in which a plurality of pairs of fiues are disposed in such a way, that the flam'e forms a double horse shoe, Fig. 8. is a horizontal section of Fig. 7, Fig. 9, is a longitudinal section of a furnace provided at the rear of the hearth with a subsidiary chamber and having a pair of fiues disposed at the rear of andnon opposite sides of the subsidiary chamber, and Fig. 10, is a horizontal section of Fig. 9.

` Referring to the example' illustrated in Figs. 1 and 2, the hearth of the furnace con sists of a section m of higher temperature and a section n of lower temperature. The material is gradually advanced through the section n to the section m while being heated to the desired temperature. The heating In said drawings Figure 1, is a vertical' the inlet and outlet fiues are disposed at the gas and air are supplied to and withdrawn from the section m alternately through flues or passages a and b disposed at opposite sides of the said section. As shown the flues are disposed vertically so that the flame passes through the section m. in a direction substantially perpendicular to the direction of the movement of the material, and in the form of a flat bow disposed in a vertical plane, as is indicated by the arrows shown in Fig. 1. A part of the flame isdirected through the section n of lower temperature, as is indicated in Fig. 2.

In the modification shown in Figs. 3 and 4 the flues a' and b' are disposed at the rear end of the section c' of higher temperature and the part of the top wall of the section 0' adjacent to the flues is inclined upward and forward, so that the flame can follow its natural tendency to move upward. Therefore the horse shoe flame is formed in an inclined plane, and the chord of the are formed by the flame is perpendicular to the longitudinal'axis of the furnace. As shown the horse shoe shaped flame is form'ed within a subsidiary chamber 0 located at the rear o'f the 'hearth c', and a part of the flame is withdrawn from the ,ehamber without coming in contact with the material to be heated, while the remaining part passes over the hearth c'.

In the example shown in 5 and 6 the flues a and b for the gases of combustion are disposed at the .rear of the hearth and vertically above each other. Thereby the flame is formed in a vertical plane and. its incoming and return branches are parallel to the longtudinal axis of the furnace. The incoming branch of the flame falls on'the material from above, whereby in case of an oxidizing flame oxidation of the material is assisted.- x

Figs. 7 and 8 ,show an example in which the flame is formed in a similar way as in Figs. 5 and 6. But instead of [being provided with a single pair of bumers, as in the example shown in Figs. 5 and 6, the furnace is provided with a plurality of pairs of burners. 'As shown three bumers are provided, and the gas enters the furnace from a chamber d and is mixed with the combustion air which is admitted through a passage e disposed above the chamber d.

` Thereby a flame is formed which is divided into two branches flowing to opposite sides of the furna'ce. The flame has the form of a double horse Shoe. From the incoming branch of the flame a part is directed through thehearth section of lower temperature, and two returning branches are withdrawn through the flues b' and f.- Figs. 7 and 8 also-show, that my improved system mayalso be used in a furnace provided with recuperato'rs. In this case the admission of the combustible gases can not be reversed,

but always takes place through the same burners.

In the furnace 'shown in Figs; 9 and 10 the subsidiary chamber g is constructed in a more distinct manner, than in the example shown in Figs. 3 and 4. The flues a* and b* aredisposed at the rear of and at o osite sides of the subsidiary chamber.. y ithin the chamber g the flame is divided in a manner similar to the example shown in Figs.` 5 and 6. A small part of the flame has the form 'of a horse shoe and is directed through the outlet flues h, while the major part passes over the hearth. The subsidiary chamber g is preferably provided in furnaces for roasting iron or zinc ores, for burning cement, for fritting ores and powder of slag. Any suitable means may be provided for feeding the material toward the flame. r

The subsidiary'chamber may be used in any of the furnaces described above and also in a furnace in which the flame is formed in a horizontal plane.

From the description it will be understood, that my improved system may be used under various conditions. The con struction of the furnace does not depend upon a determined plan, and it adapts itself to various local conditions and to the space which'is at disposal for the Construction of the furnace. For example a welding fur- .nace may be connected with a plurality of chambers of lower temperature,' within which articles of small size may be heated. In a furnace of the Construction described in my Austrian patent only one of the heating chambers would receive the whole flame', viz. the chamber located at the side of the discharge of the flame. Also in other cases it is necessary to symmetrically distribute the flame, which is possible only where the furnace is constructed according to my improved system. In some cases it is necessary to subject the material to be heated to a heavy oxidation. In such cases the horse Shoe flame is formed in a vertical plane so that it is always directed against the material located within the welding furnace. Other uses of my improved furnace will readily suggest themselves to those skilled in the art.

By providing a subsidiary chamber I am able to supply-the regenerators with ses which are free of dust. Apart from ths an important advantage is obtained where materials are to be treated which do not give of any dust. For example, in a furnace of the Construction so far describedin which no subsidiary chamber is provided, it is impossible to work under pressure. However, in a welding furnace it is very desirable, if not absolutely necessary, to work under pressure. 'Obviously at the part of the furnace where the fiame is being divided a vacuum must be produced. When withdrawing the heated material from the furnace cold air is drawn in through the doors or other openings of 'the furnace which must necessarily be provided at the said part of the turnace. However the admisson of cold air is Very objectionable. By separating the flame within the subsidiary chamber the furnace itself can be held under pressure., The said subsidiary chamber should not have any connection with the atmosphere. It will therefore be understood, that by providing my improved furnace with 'a subsidiary chamber it may be worked under pressure.

Tn all of the figures of drawing the walls of the furnaces illustrated confine the gases in the furnace and afford means adjacent the air and gas ports that coperate therewith, or assistin directing the gases from one port or set of ports to the other port or set oi" ports.

T claim herein as my invention:

1. The combination in an open hearth furnace, of air and gas ports arranged to cooperate with the furnace structure to direct a reversing flame over a portion of the hearth out of its normal horizontal plane.

2. The combination in an open hearth furnace, of air and gas ports arranged to cooperate with the furnace structure to direct a reversing flame over a portion of the hearth out of its normal horizontal plane, and means to cause a portion of said flame to extendlongtudinally over the hearth.

3. The combination in an open hearth fur nace, With a continuous hearth and regenerators; of air and gas ports coperating With the furnace structure and arranged to direct a reversing flame across a portion of the hearth out of its normal horizontal plane and normal direction between the regenerators.

4. in an open hearth furnace', the combinaton with a continuous hearth and regenerators, of air and gas ports arranged to cooperate with the furnace structure to direct a reversing flame across a portion of the hearth out of its normal horizontal plane and normal direction between the regenerators, and another portion of said flame longitudnally over the remaining portion of thehearth.

5. In an open hearth furnace in combination; a hearth, air and gas ports; and means coperating therewith to direct the flame over a portion of the hearth into a plurality of reversed portions.

6. ln an open hearth furnace in combinetion; a hearth, air and gas porte, and means coperating therewith to divide the flame over a portion of the hearth into a plurality of reversed portions directed out of their normal path in planes at an angle to the horizontal. 4

7. In an open hearth furnace, the combination with the hearth and air and gas ports; of means coperating with said ports to divide the flame into a plurality of re-'` `versed portions directed transversely of the hearth in planes at an angle to the horizontal.

8. In an open hearth furnace, the combination With the hearth and air and gas ports; of means coperating with said ports to divide the flame into a plurality of reversed portions directed transversely of the hearth in planes at an angle to the horizontal, and means to direct a portion of the flame longitudinally of the hearth.

' 9. In an open hearth furnace in combination; the hearth, the air and gas porte thereof, and means coperating with said ports to ;direct all of the flame over the initial portion of the hearth, a portion of said flame being reversed and defiected from its normal path and means to cause another portion to extend over the entire hearth;

In testimony whereof I hereunto aflix my signature in the presence of two witnesses.

. FRIEDRICH SIEMENS.

Witnesses;

HENRY HASPER, WOLDEMAR -HAUPT. 

